NAGAI Tsukasa

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Organization: AIST , Japan
Department:
Title: (PhD)
Co-reporter:Tsukasa Nagai, Shin-ichi Yamazaki, Masafumi Asahi, Zyun Siroma, Naoko Fujiwara, Tsutomu Ioroi
Journal of Power Sources 2015 Volume 293() pp:760-766
Publication Date(Web):20 October 2015
DOI:10.1016/j.jpowsour.2015.06.004
•We prepared cobalt octaethylporphyrin (Co-OEP)-modified perovskite/carbon catalysts.•ORR activity of perovskite/carbon was enhanced by Co-OEP-modification.•RRDE measurements suggested that the 2 + 2 electron reduction of O2 is promoted.•The porphyrin plays a role as a two-electron O2 reduction catalyst to give HO2−.•HO2− is further reduced to OH− by the perovskite-type oxide.Perovskite-type oxide-carbon (Vulcan XC72) mixture (La0.6Sr0.4Mn0.6Fe0.4O3/C) was modified by a metalloporphyrin (cobalt octaethylporphyrin: Co-OEP) having two-electron O2 reduction activity, and its electrochemical reduction activity for O2 (ORR) was investigated in an alkaline solution by rotating ring disk electrode (RRDE) voltammetry. The Co-OEP/La0.6Sr0.4Mn0.6Fe0.4O3/C catalyst showed improved ORR activity, with a positive shift of the onset potential. In addition, a decreased ring current compared to Co-OEP/C suggested that the quasi-four-electron reduction of O2 was also enhanced. Further experiments showed that ORR activity was also enhanced by Co-OEP-modification of other types of carbon (Ketjenblack EC600JD, Denka Black) or perovskite-type oxide (La0.6Ca0.4Mn0.6Fe0.4O3, La0.8Sr0.2Co0.6Fe0.4O3). In the case of the addition of other porphyrin complexes (cobalt tetraphenylporphyrin (Co-TPP), iron octaethylporphyrin (Fe-OEP)) to a La0.6Sr0.4Mn0.6Fe0.4O3/C catalyst, the onset potential did not shift to the positive side due to the lower activity compared to Co-OEP.
Cobalt, [2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphinato(2-)-κN21,κN22,κN23,κN24]-, (SP-4-1)-
Perchlorate (8CI,9CI)
Iron, chloro[2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphinato(2-)-κN21,κN22,κN23,κN24]-, (SP-5-12)-
21H,23H-Porphine, 2,3,7,8,12,13,17,18-octaethyl-